/**
	JSON parsing and stringifying with support for id and path based referencing.
	by Kris Zyp - www.xucia.com
	Uses the "old" JSON JS API that does not break enumerability.
	Modified version of the Douglas Crockford's JSON library from http://www.json.org/js.html
    Public Domain? How are you supposed to license something when you modify public domain code?
    Usage: 
    JSON.stringify(value) turns a JS value into JSON string. When an object is encountered more
    than one (through circular or multiple referencing), a reference is made to it.
    JSON.parse(string) turns a JSON string into a JS object. When a reference is encountered it is resolved.
     References are in the form of:
    {"$ref":"$|id.path"}     
*/
(function() {
  var ids={};
  JSON= {
  	resolveRef: function(ref) {
		throw new Error("Reference to " + ref + " could not be resolved");  		
  	},
     stringify: function (v) {
	   var a = [];
	   var paths={};
	   var m = {
	       '\b': '\\b',
	       '\t': '\\t',
	       '\n': '\\n',
	       '\f': '\\f',
	       '\r': '\\r',
	       '"' : '\\"',
	       '\\': '\\\\'
	   };
	   function e(s) {
	       a[a.length] = s;
	   }
	   function s(x) {
            if (/["\\\x00-\x1f]/.test(x)) {
               return '"' + x.replace(/([\x00-\x1f\\"])/g, function(a, b) {
                   var c = m[b];
                   if (c) {
                       return c;
                   }
                   c = b.charCodeAt();
                   return '\\u00' +
                       Math.floor(c / 16).toString(16) +
                       (c % 16).toString(16);
               }) + '"';
           }
           return '"' + x + '"';
	   }
	   function g(x,p) {
	       var c, i, l, v;
	       switch (typeof x) {
	       case 'object':
	           if (x) {
	               if (x instanceof Date) {
				        function f(n) {
				            return n < 10 ? '0' + n : n;
				        }

				        return e('"' + this.getUTCFullYear() + '-' +
				                f(this.getUTCMonth() + 1) + '-' +
				                f(this.getUTCDate()) + 'T' +
				                f(this.getUTCHours()) + ':' +
				                f(this.getUTCMinutes()) + ':' +
				                f(this.getUTCSeconds()) + 'Z"');
                    }
                    // ref ->
                   if (x.id) {
                    	if (ids[x.id] || paths[x.id]) 
                    		return g({$ref:x.id});
                    	else
                    		ids[p = x.id] = x;
                   	}
                   	else {
                   		x.id = p;
                   		paths[p] = x;
                  	}
                   // <- ref
	               if (x instanceof Array) {
	                   e('[');
	                   l = a.length;
	                   for (i = 0; i < x.length; i += 1) {
	                       v = x[i];
	                       if (typeof v != 'undefined' &&
	                               typeof v != 'function') {
	                           if (l < a.length) {
	                               e(',');
	                           }
	                           g(v,p +'['+i+']');
	                       }
	                   }
	                   e(']');
	                   return;
	               } 
	                    else if (typeof x.valueOf == 'function') {
	                        e('{');
	                        l = a.length;
	                        for (i in x) {
	                            v = x[i];
	                            if (typeof v != 'undefined' && !(i == 'id' && paths[v]) &&
	                                    typeof v != 'function' &&
	                                    (!v || typeof v != 'object' ||
	                                        typeof v.valueOf == 'function')) {
	                                if (l < a.length) {
	                                    e(',');
	                                }
	                                e(s(i));
	                                e(':');
	                                // -> ref
	                                g(v,p+(i.match(/^[a-zA-Z]\w*$/) ? ('.' + i) : ('[' + s(i) + ']')));
	                                // <- ref
	                            }
	                        }
	                        return e('}');
	                    }
	                }
	                e('null');
	                return;
	            case 'number':
	                e(isFinite(x) ? +x : 'null');
	                return;
	            case 'string':
	            	e(s(x));
	                return;
	            case 'boolean':
	                e(String(x));
	                return;
	            default:
	                e('null');
	                return;
	            }
	        }
	        g(v,'$');
	        for (i in paths) 
	        	delete paths[i].id;   
	        return a.join('');
	    },
	parse : function(str,stop) { 
			var j,ref,rw=[];
            function walk(v,stop) {
           	    // ref ->
            	if (v.id)
					ids[v.id] = v;
            	for (var i in v) {
					if (v.hasOwnProperty(i) && (typeof (val=v[i]) =='object') && val) {
						if (ref=val.$ref) {
							var stripped = ref.replace(/\\./g, '@').replace(/"[^"\\\n\r]*"/g, '');
							if(/[\w\[\]\.\$ \/\r\n\t]/.test(stripped) && !/=|((^|\W)new\W)/.test(stripped)) {
								var path = ref.match(/(^[\$\w]+)(\W.*)?/);
								(ref=path[1]=='$'?j:ids[path[1]]) ?
									(v[i] = path[2] ? eval('ref' + path[2]) : ref) : (stop ? JSON.resolveRef(val.$ref) : rw.push(v)); 
							}
						}
						if (!stop) // <- ref
							walk(val,rw==v);
					}
				}
            }
            if (/^[,:{}\[\]0-9.\-+Eaeflnr-u \n\r\t]*$/.test(str.
                    replace(/\\./g, '@').
                    replace(/"[^"\\\n\r]*"/g, ''))) {
                j = eval('(' + str + ')');
                walk(j);
                walk(rw);
                return j;
            }
            throw new SyntaxError('parseJSON');
        }
	}
})();
